ES2309618T3 - CONJUGATES OF LHRH-PEG ANALOGS. - Google Patents

Abstract

PEG-LHRH analog conjugates, where a PEG moiety is covalently bound to a serine residue of a LHRH analog, and methods for producing these conjugates are provided in the present invention. Also provided are a pharmaceutical composition and a method for treating pathologies in which LHRH analog administration is beneficial.

Description

Analog conjugates of LHRH-PEG.

Field of the Invention

The present invention relates to conjugates of LHRH-PEG analogues in which the PEG unit is covalently bound to Ser4, either directly or by means of a bifunctional crimping molecule such as a amino acid Its use in therapeutic treatment, in which it is It is advisable to administer LHRH analogues, it is an object of The present invention.

Foundation of the invention

The covalent bond of the hydrophilic polymer polyethylene glycol, (PEG), also known as poly (oxide of ethylene) (PEO), with molecules, has important applications in Biotechnology and medicine. In its most common form the PEG is a linear polymer that has hydroxyl groups in each of its extremes:

HO-CH 2 -CH 2 O (CH 2 CH 2 O) n CH 2 CH 2 -OH

This formula can be briefly represented. as HO-PEG-OH, in which understand that -PEG- represents the main chain without the groups terminals:

"-PEG-" it means "-CH 2 -CH 2 O (CH 2 CH 2 O) n CH 2 CH 2 -"

PEG is commonly used as methoxy-PEG-OH, (m-PEG), in which one end is the methoxy group, relatively inert, while the other end is a group hydroxyl that is subject to chemical modification:

CH 3 O- (CH 2 CH 2 O) n -CH 2 CH 2 -OH

Branched PEGs are also commonly used. The Branched PEGs can be represented as R (-PEG-PH) m in whose formula R represents a core core residue such as pentaerythritol or glycerin, and m represents the number of branching arms. He number of branching arms (m) can vary from three to one hundred or more. Hydroxyl groups are subject to modification. chemistry.

Another branched form, such as that described in PCT patent application, WO 96/21469, has a single terminal subject to chemical modification. This type of PEG can be represented as (CH 3 O-PEG -) p RX, in which formula p is equal to 2 or 3, R represents a central core such as lysine or glycerin, and X represents a functional group such as carboxyl that is subject to chemical activation. Yet another branched form, the hanging PEG has reactive groups
Tives, such as carboxyl, along the main PEG chain instead of at the end of the PEG chains.

In addition to these forms of PEG, the polymer can also prepare with weak or degradable links in the chain principal. For example, Harris has indicated in the application for U.S. Patent 06 / 026.716, which can be prepared PEG with links ester type in the polymer main chain, which are subject to hydrolysis. This hydrolysis results in the segmentation of the polymer in fragments of lower molecular weight, according to the scheme reaction:

-PEG-CO 2 -PEG-  + H 2 O → -PEG-CO 2 H + HO-PEG-

As used herein, it is understood that The term polyethylene glycol or PEG includes all derivatives previously described.

The copolymers of ethylene oxide and oxide propylene are closely related to the PEG in their chemical properties, and can be used instead of PEG in Many of its applications. These compounds have the formula General following:

HO-CH 2 CHRO (CH 2 CHRO) n CH 2 CHR-OH

in whose formula R is H or CH_ {3}.

PEG is a useful polymer that has the property of high water solubility as well as high solubility in many organic solvents. The PEG also does not It is toxic and is not immunogenic. When PEG chemically binds (PEGylation) to a water insoluble compound, the conjugate that it turns out to be generally soluble in water as well as soluble in many organic solvents.

The luteinizing hormone releasing hormone (LHRH or GnRH) is a decapeptide secreted by the hypothalamus, capable of inducing the release of LH and FSH, both. Owns the formula next:

pyroGlu-His-Trp-Ser-Tyr-Gly-Leu-Arg-Pro-Gly-NH_ {2}.

LHRH can either stimulate the secretion of pituitary gonadotropin, or be a potent inhibitor. When administered according to a precise pulsatile pattern, LHRH can restore normal secretion of cyclic gonadotropin. The pulsatile administration of LHRH using a computerized pump has been employee with good results for ovulation induction in Anovulatory women with hypothalamic dysfunction. When has administered chronically, LHRH or its agonists have demonstrated be potent inhibitors of gonadotropic secretion, providing a temporary medical hypophysectomy (fully reversible), specific, of gonadotropins.

To date, thousands of LHRH analogues, which can act either as agonists or as antagonists In order to produce LHRH antagonists, which act by occupation of the receiver, it is necessary to replace several existing amino acids in the LHRH molecule. Antagonists they also require precise topological characteristics to achieve high affinity of receptor binding. There are many recently synthesized LHRH analogs, in which the amino acids contain aromatic groups or other functional groups capable of the so-called hydrotropic interaction. The use of LHRH antagonists with their immediate release inhibition Gonadotrophin, may be useful in therapeutic fields, such as contraception, and in the treatment of conditions dependent on hormones In the case of hormone-dependent tumors, it can be a particular advantage of avoiding the initial stimulating phase produced by LHRH agonists. For a review of analogues of the LHRH, see Karten and Rivier, 1986.

The antide, in particular, is an antagonist potent of LHRH, with formula, biological activity and preparation as described in EP 377,665, and indicated continuation in this memory.

one

[Acetyl-D-3- (2'-naphthyl) -alanine) 1, D- (4-chlorophenyl) -alanine 2, D-3- (3'-pyridyl) -alanine 3, Lysine (NE-nicotinoyl) 5, D-lysine (NE-nicotinoyl) 6, Lysine (NE-Isopropyl) 8, D-alanine 10] - releasing hormone Gonadotropin (GnRH)

Starting from studies carried out, it has discovered, for example, that the antide has a very soluble solubility poor in 0.9% NaCl solution (25 µg / ml solubility) or others isotonic media such as phosphate buffered saline (the solubility was 16 µg / ml). The above formulations of antide (for example, antide, 1 mg / ml, in 5% glucose) have put manifestly poor bioavailability and reproducibility Pharmacokinetics

Covalent binding of PEG to peptides is a potentially useful approach to distribute peptide drugs insoluble in water, as indicated by Felix (A.M. Felix en J.M. Harris and S. Zalipsky, Compilers, Poly (ethylene glycol) Chemistry and Biological Applications, A.C.S. Symposium Series 680, pages 218-238, A.C.S. Washington, DC 1997).

JP patent application, JP 3148298, describes peptide conjugates (for example, including GnRH) -PEG obtained by reacting with PEG the guanidino group, present, for example, in the rest of arginine, at time the amino groups present in the molecules are protected. WO 94/27641 refers to conjugates of drug-polymer

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Mention of any document in this memory is not considered as an admission that such a document is relevant prior art, or that is a material considered regarding the patentability of any claim of the present patent application. Any reference as to your content or date of any document is based on the information available to applicants at the time of presentation and do not constitute admission as to the accuracy of such reference.

Summary of the invention

This invention provides new conjugates of LHRH-PEG analogues, in which a PEG unit is covalently bound to Ser4, either directly, or by means of a bifunctional linker molecule, such as a amino acid The PEG or the PEG crimp molecule is attached, specifically, to the alcohol function of the rest of serine. He crimp between the LHRH analogue and the polyethylene glycol or molecule of crimping the PEG in these conjugates, is subject to hydrolysis in a physiological pH (7.2 - 7.4) and is also subject, preferably, hydrolysis by esterases present in the blood.

Brief description of the drawings

Figure 1 shows a reaction scheme for prepare an antide-PEG conjugate. with a crimp of glycine inserted between the PEG and the remains of the antide.

Figure 2 shows the graphs of Capillary Electrophoresis (EC) of hydrolysis of the conjugate of antida-PEG, at 37 ° C, in phosphate buffer solution pH 7.2, at t = 0.460 and 1395 minutes.

Figure 3 shows the graph of the kinetics of deduced hydrolysis of the data in Figure 2 assuming a First order pseudo kinetics.

Detailed description of the invention

The conjugates of the present invention, preferably, they exhibit a water solubility of 30 mg / ml, per at least at room temperature and physiological pH (7.2-7.4), and a solubility in a saline solution physiological 10 mg / ml, at least in them terms.

In the event that the analogue of the LHRH is antida, for example, such properties allow the use of the antide as a drug, while, previously, the development of antide as a drug has been considered difficult due to its bad water solubility.

The expression "analogues of LHRH", such as used herein, it is understood to include a decapeptide which is an antagonist of LHRH. Preferably, the analog of the LHRH is antide.

The conjugates of the present invention can be prepared by any of the methods known in the technique. According to an embodiment of the invention, the LHRH analog it is reacted with a PEGylation agent, within a suitable solvent, and the desired conjugate is isolated and purified, by example, using one or more chromatographic methods.

"Chromatographic methods" means any technique used to separate the components of a mixing through application on a support (stationary phase) through which a solvent circulates (mobile phase). The Chromatography separation principles are based on the different physical nature of the stationary phase and the phase mobile.

Some particular types of methods chromatographic, well known in the scientific literature, include liquid chromatography, high liquid chromatography pressure, ion exchange chromatography, chromatography absorption, affinity chromatography, partition, hydrophobic, of inverted phase, gel filtration, ultrafiltration or chromatography in thin layer

The "PEGylation agent", as used in the present patent application, means any PEG derivative capable of reacting with the OH of a serine moiety or a functional group of a bifunctional linker molecule, such as the amino group of a molecule of a crimp amino acid. The other functional group of the linker molecule serves to form a covalent bond with the serine moiety of an LHRH analog, that is, the carboxyl group of a linker amino acid molecule forms an ester-type bond with the serine. It may be an alkylation reagent such as a PEG aldehyde, PEG epoxide or PEG three-oxide, or it may be an acylation reagent, such as
PEG-O- (CH 2) n CO 2 -Z, in which formula n = 1-3 and Z is an N-succinimidyl group or other suitable activation group.

The PEGylation agent is used in its form mono-methoxylated when only one of its terminals is available for conjugation, or in a way bifunctional when both terminals are available for conjugation, such as, for example, to form a conjugate with two LHRH analogues covalently linked to a single PEG residue. It has a molecular weight between 500 and 100,000, preferably between approximately 5,000 and 40,000 (40 kDa) and more preferably, between approximately 10 kDa and 40 hDa, and, most preferably, between approximately 20 kDa and 40 kDa.

If the PEGylation agent is an acylation agent, it may contain either a norleucine or ornithine moiety attached to the PEG unit via an amide linkage. These residues allow a precise determination of the bound PEG units, per mole of peptide (see, for example, Sartore et al ., 1991).

The solvent for the PEGylation reaction is, preferably, a polar aprotic solvent, such as DMF, DMSO, pyridine, etc.

When the LHRH analog is reacted with the PEGylation agent, derivatization can take place on the OH of the serine 4 residue, as well as on the amide nitrogen of other moieties, such as, for example, on the group \ lysine varepsilon-amino (in the case of the antide, on the N-Isopropyl-Lys 8). In such reactions, high selectivity for PEGylation of amines can take place. The products formed by PEGylation on amines are amides, and although the PEG amides may be soluble in water, the amide bond may be stable under physiological conditions and, therefore, the LHRH analog may not be hydrolytically released, so substantial, in vivo . Therefore, using this method, the ester of the LHRH-PEG analogue must be separated from the amide of the LHRH-PEG analog using chromatography. A limitation of this method is, therefore, the low yield of the conjugate of the desired LHRH-PEG analog.

Therefore, in a preferred embodiment, the LHRH analogue is protected in amino groups that could either reacted with the PEGylation agent or with a molecule bifunctional crimping before PEEGilation.

In the case of the antide, it is preferable, for consequently, reversibly protect the rest of N-Isopropyl-Lys 8 with a group that can be separated using photochemical, hydrolytic methods soft or hydrogenation. With nitrogen protected in this way, the hydroxyl group of the serine moiety is reacted with a PEGylation reagent to form a PEG ester and the group of protection over N-Isopropyl-Lys 8 separates then obtaining the PEGylated antide selectively on the group hydroxyl of the serine moiety through an ester type bond. The conditions for separation of the protection group from the group amino should be gentle enough to avoid segmentation of the ester type bond of the conjugate of antida-PEG. In another embodiment in which uses a bifunctional crimp molecule or a molecule spacer to link a PEG residue with an LHRH analog such like the antide, the protection group is preferably separated after a bifunctional crimp molecule is attached covalently to the serine moiety of an LHRH analog or may separate after PEGylation of the bifunctional molecule of crimp covalently linked to the LHRH analog.

Preferred reagents for protection include benzyloxycarbonyl chloride or derivatives thereof ring substituted compound, esters of N-hydroxysuccinimidyl or 1-benzotriazolyl of a benzyloxycarbonic acid or substituted derivatives in the chloride ring of t-butoxycarbonyl or esters of N-hydroxysuccinimidyl or 1-benzotriazolyl acid t-butoxycarbon.

In another embodiment of the invention, the conjugates of the invention can be prepared using a serine Appropriate PEGylated such as Fmoc-Ser (PEG) -OH or tBoc-Ser (PEG) -OH, instead of serine, during solid phase synthesis of the analogs of the LHRH An example of a derivative of Fmoc-Ser (PEG) -OH is shown at continuation.

2

A regulation of the degree of in vivo release of the LHRH analog can be achieved by varying n and R in the PEG bond. In general, as n increases, the degree of LHRH analog release decreases, and if R is alkyl, the degree of LHRH analog release is less than the degree of release if R is H. In general, as that the size of R increases, the degree of release of the LHRH analog, or the antide in particular, decreases the variation of n and R, therefore, substantially provides precise control of the degree of in vivo distribution of the antide when used as drug.

According to recent studies, such as the patent from the USA 5,840,900, the highest molecular weight PEG appears to be important to obtain therapeutic efficacy in certain cases. For la antida, three antide-PEG conjugates with PEGylating agents that have molecular weights of 20 kDa or 40 kDa, have been prepared by modifying the operative procedure of protection-deprotection. In one embodiment preferred, the degree of PEGylation of the antide, in particular with PEG residues of higher molecular weight, is increased by setting in first to the antide a crimp molecule, such as glycine and then PEGylating the covalently linked linker molecule to the antide. The reaction scheme to prepare a PEGylated antide with a glycine crimp, is shown in Figure 1. The scheme of Figure 1 can be used to prepare, for example, conjugates such as anti-glycine-PEG 20k (may use a branched PEG of 20kDa), anti-glycine-mPEG (can be used  a linear mPEG of 20 kDa), and anti-glycine-PEG2 40 k (may use a branched PEG of 40 kDa). It will be appreciated by skilled in the art, that the scheme indicated in Figure 1 is not limited to antide or glycine crimp but can be applied to other analogs of LHRH and other linker molecules.

The crimp molecule is preferably a small bifunctional molecule that can react quickly with the OH group of the serine moiety of an LHRH analog. This molecule Crimp is preferably a crimp molecule heterobifunctional, such as an amino acid, that forms an ester with a serine residue of an LHRH analog. The second functional group of the linker molecule serves as a PEGylation site by the PEGylation agent. The amino acid, glycine, is the molecule of Preferred heterobifunctional linker according to the present invention. Other suitable crimp molecules can be recognized or Easily determined by those skilled in the art.

Another object of the present invention is provide the conjugates in substantially purified form with so that they are suitable for use as an active ingredient in pharmaceutical compositions for the treatment, diagnosis or prognosis of pathologies in which administration is advisable of LHRH analogues. Such pharmaceutical compositions represent Another object of the present invention.

If the analogue of LHRH is the antide, the aforementioned pathologies include endometriosis, uterine fibroids, hormone-dependent cancers (prostate, breast), uterine fibroid, overproduction of LH in women undergoing in vitro fertilization and all other pathological conditions indicated in EP 377,665.

Other embodiments and advantages of the invention they will be evident in the description that follows.

An embodiment of the invention is the administration of a pharmacologically active amount of conjugates of the invention to subjects at risk of developing a of the diseases indicated above, or to subjects who They already manifest such pathologies.

Any route of administration can be used compatible with the active substance. The preferred administration is parenteral administration, such as subcutaneous injection, intramuscular or intravenous. The dose of the active ingredient that has if administered depends on the basis of medical prescriptions according to the age, weight and individual response of the patient.

The daily dose for the patient, without taking into The weight counts, it can be between 0.2 and 20 mg, and the daily dose Preferable is between 0.2 and 10 mg.

The pharmaceutical composition for administration parenteral can be prepared in an injectable form that comprises the active substance and a suitable vehicle. Vehicles for parenteral administration are well known in the art and they comprise, for example, water, saline, Ringer's solution and / or dextrose.

The vehicle may contain small quantities of excipients in order to maintain stability and isotonicity of the pharmaceutical preparation.

The preparation of the mentioned solutions can be carried out according to ordinary modalities.

The invention will now be described by means of The following Examples.

Example one

Preparation of antide-PEG conjugate

Antide (10 mg, 6.3 mmol) was dissolved in 15 ml of anhydrous pyridine and the resulting solution was distilled azeotropically, under vacuum, at 45 ° C until they were left, approximately 8 ml of pyridine. After cooling the solution to room temperature, mPEG succinimidyl ester was added carboxymethylated (93 mg, 19 mmol, Shearwater Polymers, Huntsville, AL), and the solution was stirred for 48 hours, under nitrogen, at room temperature. Then the pyridine was removed in vacuo and collected the product by vacuum filtration after precipitation with ether (50 ml), and dried in vacuo.

The product (50 mg) obtained from the stage above, it was dissolved in deionized water (1.5 ml) and the mixture was filtered through a 0.2 ml syringe filter. The solution is loaded on an ion exchange chromatography column (CM Sepharose Fast Flow, Pharmacia, Uppsala, Sweden). Eluents were deionized water and 50 mM NaCl solution, with a gradient from zero to 60% salt solution. Three peaks were observed, the middle peak being that of the antide-PEG conjugate desired, in which the PEG chain is linked to Ser4.

This conjugate was collected by fractionation and It was lyophilized. The product showed that it was very soluble in water (> 30 mg / ml).

Conjugate hydrolysis kinetics of antida-PEG

The conjugate hydrolysis was determined using capillary electrophoresis (EC). The half-life calculated in these Conditions are 5.5 hours as illustrated in Figures 2 and 3.

Claims (9)

1. Use of a conjugate of an analogue of the luteinizing hormone releasing hormone (LHRH) -polyethylene glycol, which has a remainder of polyethylene glycol (PEG) covalently bound to a serine moiety of LHRH analog, in which the LHRH analog is an antagonist of LHRH and in which said conjugate is capable of hydrolysis to release said analog of LHRH, in the manufacture of a medicament to treat hormone dependent disorders. 2. The use according to claim 1, wherein said rest of PEG is covalently linked to said rest of serine of the LHRH analog by means of a bifunctional molecule of crimp. 3. The use according to claim 2, wherein said bifunctional crimp molecule is a molecule heterobifunctional crimping. 4. The use according to claim 3, wherein said bifunctional linker molecule forms an ester with said serine residue of the LHRH analog. 5. The use according to claim 3, wherein said heterobifunctional linker molecule is an amino acid. 6. The use according to claim 5, wherein said heterobifunctional linker molecule is glycine. 7. Use according to any one of the claims 1-6, wherein said antagonist of LHRH is antide. 8. The use according to claim 7, wherein the medicament is for treating endometriosis, uterine fibroids, hormone-dependent cancers, uterine myoma, overproduction of LH in women undergoing in vitro fertilization. 9. Use of a pharmaceutical composition that comprises an LHRH-PEG analog conjugate according to it is used according to any one of the claims 1-8 as an active ingredient and a pharmaceutically acceptable excipient or auxiliary agent in the manufacture of a drug to treat dependent disorders of hormones